Rotary hydraulic machines

ABSTRACT

A rotary hydraulic machine has a rotor journalled on a pintle which extends internally of the machine casing. The rotor has an axial bore into which the pintle extends so as to provide a space between the end of the pintle and the end of the bore. Fluid pressure within the casing is admitted to this space to partially offset the pressure urging the rotor onto the pintle.

United States Patent Freeman Sept. 25, 1973 [54] ROTARY HYDRAULICMACHINES 3,283,668 11/1966 Louhio 91/44 4 [75] Inventor: Frank GeorgeFreeman, Solihull, 3O78808 2/1963 Byers 91 England PrimaryExaminerWilliam L. Freeh [73] Assignee. Joseph Lucos (Industries)Limited, Asst-slam Examiner cregory P. La Poime Blrmmgham EnglandAttorney-Holman & Stern [22] Filed: June 28, 1971 Appl. No.: 157,386

US. Cl. 91/484, 91/491 Int. Cl. F04b 19/00 Field of Search 9l/484, 485,486,

References Cited UNITED STATES PATENTS 2/194l Ferris 91/484 [57]ABSTRACT 4 Claims, 3 Drawing Figures Pmmmsmsma 3.760.690

' sum 1 or 2 I FIGZ.

PATENTED 3.760.690 v SHEEI 2 OF 2 INVENT R kZM%M Z Mm ROTARY HYDRAULICMACHINES This invention relates to rotary hydraulic machines and has asan object the provision of such a machine in a convenient form.

According to the invention a rotary hydraulic 'machine comprises acasing, a pintle extending into the casing, a rotor mounted on thepintle, the said rotor having an axial bore into which the pintleextends so as to define a space between the end of the pintle and theend of the bore, an annular part disposed eccentrically of the rotor, aplurality of pistons slidable in radial bores in the rotor and engagingan inner surface of the annular part and a passage in the rotor wherebya fluid pressure within the casing is admitted to the said space betweenthe axial bore and pintle, the arrangement being such that the sum ofthe axial forces on the rotor has a desired value and acts in adirection to urge the rotor on to the pintle.

A hydraulic motor according to the invention will now be described byway of example and with reference to the accompanying drawings in which:

FIG. 1 is a section through a motor,

FIG. 2 is a section of line 2-2 in FIG.'1; and

FIG. 3 is a scrap view, to a different scale, of a part of FIG. 1.

The motor has a casing formed in two parts 10, 11. Part has an integralpintle 12 within which are passages 13, 14 which communicate'withrespect ports 15, 16 opening on to the surface of the pintle l2.Passages l3, 14 also communicate respectively with an inlet (not shown)and an outlet 17 for the motor. A rotor mounted on the pintle 12includes a cylinder member 18 and a shaft 19 secured to the member 18 bya stepped flange 19a.

The dimensions of the member 18 and pintle l2.are such as to define anannular space 20, shown more clearly in FIG. 3, between the end of thepintle l2 and the flange 19a of the shaft 19. The flange 19a is engagedon opposite sides by a pair of bearing seal rings 21,22 each having alow co-efficient of friction. Rings 21, 22 are carried by bushes 23, 24respectively sealingly and slidably engaged in an end wall of the bodypart 11 and in the pintle 12. Spring washers 25, 26 act to urge thebushes 23, 24 respectively towards the flange 19a, and hence theassociated rings 21, 22 into close engagement with the flange 19a. Apassage 27 in the cylinder member 18 allows the annular space tocommunicate with the interior of the casing 10, 11.

The cylinder member 18 is formed with two rows of stepped radial bores28, a piston 29 being slidable in each bore 28. Each piston 29 has aslipper 30 secured thereto by a hollow rivet 31. The casing part 11 isformed internally with a pair of part-spherical surfaces 11a disposedeccentricallywith respect to the cylinder member 18. Slippers engage thesurfaces 11a.

In use, hydraulic fluid under pressure is supplied via the inlet andpassage 15 .to operate the motor in a known manner, and is subsequentlydischarged via passage 16 and outlet 17. Fluid at a high pressure isalso admitted to the interior of the casing via an orifice not shown)opening into the motor inlet. This fluid pressure acts on the end facesof the cylinder member 18, the difference in the areas of the end facesresulting in a force tending to urge the rotor to the right, as shown inFIG. 1. The same fluid pressure enters the space 20 via passage 27 andacts upon flange 19a, tending to urge the rotor to the left. Theresultant force on the rotor is thus reduced, though still tending tourge the rotor to the right. The resultant force may, by themrangementdescribed, be maintained at a desired value without the necessity ofmaking the shaft 19 an unacceptably large diameter. Fluid leaking intothe bore of bush 24 escapes to low pressure via an axial passage 32 inshaft 19.

it will be understood that an arrangement substantially as describedabove may also be used as a pump, in which case a liquid is drawn in viaport 16 and discharged under pressure through port 15'.

I claim:

1. A rotary hydraulic machine comprising a pressure fluid containingcasing, a ported pintle extending into the casing, a rotor mounted onthe pintle and comprising a cylinder member and a flanged shaft securedthereto said cylinder member, having an axial bore into which the pintleextends, a part extending axially from the end of the pintle andsealingly engaged with the flange of said shaft so as to define a closedannular space between the end of the pintle and said flange, an annularpart disposed excentrically of the rotor, a plurality of pistonsslidable in radial bores in the cylinder member and engaging an innersurface of said annular part and a passage in the cylinder memberwhereby the fluid pressure contained within the casing is admitted tosaid closed annular space, whereby a force caused in use by a fluidpressure acting on the rotor to urge the rotor on to the pintle ispartially offset by an opposing force on the rotor caused by fluidpressure acting in said closed annular space.

2. A machine as claimed in claim 1 in which said axially extending partcomprises a bush sealingly slidable within said end of the pintle andthere is provided means for biasing said bush towards said end of theaxial bore 3. A machine as claimed in claim 2 which includes a sealingring carried by said bush and engaging said end of the axial bore.

4. A machine as claimed in claim 3 in which said sealing ring has a lowcoefficient of friction.

1. A rotary hydraulic machine comprising a pressure fluid containingcasing, a ported pintle extending into the casing, a rotor mounted onthe pintle and comprising a cylinder member and a flanged shaft securedthereto said cylinder member, having an axial bore into which the pintleextends, a part extending axially from the end of the pintle andsealingly engaged with the flange of said shaft so as to define a closedannular space between the end of the pintle and said flange, an annularpart disposed excentrically of the rotor, a plurality of pistonsslidable in radial bores in the cylinder member and engaging an innersurface of said annular part and a passage in the cylinder memberwhereby the fluid pressure contained within the casing is admitted tosaid closed annular space, whereby a force caused in use by a fluidpressure acting on the rotor to urge the rotor on to the pintle ispartially offset by an opposing force on the rotor caused by fluidpressure acting in said closed annular space.
 2. A machine as claimed inclaim 1 in which said axially extending part comprises a bush sealinglyslidable within said end of the pintle and there is provided means forbiasing said bush towards said end of the axial bore
 3. A machine asclaimed in claim 2 which includes a sealing ring carried by said bushand engaging said end of the axial bore.
 4. A machine as claimed inclaim 3 in which said sealing ring has a low coefficient of friction.